SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e6d4a639795eea0c7728cc3dab90578218a78fa3874929eff0dcb9605b6032f' 
  AND token = 'p+kheDUv201QuW2wshxJ//mc9JfcMVChGFYbCAR3hlU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}